Generally, the existing compound sealing methods for glass plates are as follows:
(1) Use fits with a low melting point to be melted for sealing, wherein the sealing temperature is 400-500° C. or so in general, and by means of flame or electrical heating, the fits with the low melting point are melted so as to complete the compound sealing between the glass plates. The glass with the low melting point used by the process is usually PbO—ZnO sealing glass, and such material is hardly conducive to environmental protection requirements for its future development since lead is harmful to the environment and human bodies. Meanwhile, equipment and processes for manufacturing the material are complicated, and the glass plates after compound sealing also can generate boundary heat stress frequently, thereby needing an additional proper annealing treatment which greatly lowers the production efficiency. In addition, if this process is adopted to seal toughened glass, the glass will lose its safety properties due to glass annealing.
(2) Adopt various plastic or resin materials to carry out the compound sealing between the glass plates. Some patent documents mention that organic glasses such as PC, ABS, LDPE, PVC and the like are used, laminated glass materials such as PVB, EVA (EN) and the like are used in some patent documents, and processing methods are both as follows: place the above materials between two glass plates to be made into prefabricated parts, and then press the prefabricated parts under appropriate conditions. Such process is similar to the process for manufacturing laminated glasses, and can realize the compound sealing between glass plates. However, it is difficult to guarantee the leak tightness at the joints because the gas permeability and moisture permeability of majorities of the plastic and resin materials are far greater than those of glasses and majorities of the organic materials are only physically bonded with surfaces of the glass plates; and decrease in sealing strength, interlayer dewing and mildewing of glass will be directly caused in case of permeation of gases (including water vapor). In addition, the aging of the organic material will have a direct influence on the sealing effect and life of the compounded glass plates as time goes on.
(3) In order to eliminate the annealing problem in the process of sealing the toughened glasses, many patent documents mention a method of section-compartmentalized heating, i.e. locally heating the sealing position by means of microwave, high frequency, infrared ray, laser or the like to directly melt edges of two or more glass plates together under the condition of keeping a low temperature of the glass plate bodies; and some documents mention a photosensitive curing method is used to carry out the compound sealing between the glass plates. However, these methods are still in the contemplation or lab stage, and no such mature technology or products have been brought to the market. Besides, the aging of the bonding material remains even though an optical light-sensitive is used for the compound sealing between the glass plates.